Tomorrow will be my 36th anniversary with IBM!!
The first piece of equipment I learned to operate was a Tektronix 576 curve tracer. I used it to do to Vfb, and Ir measurements on GaAs LED chips. Imagine that, LEDs 36 years ago!
Several years ago, I bought one of these Tektronix 576 curve tracers off of E-bay for my shop.
In addition to my scope, the piece of equipment I use the most is the Tektronix 576 curve tracer. I use it for testing semiconductor devices (diodes, bipolar & FET transistors, triacs, SCRs, etc.). You can measure forward voltages, reverse leakages, breakdown voltages, bipolar transistor hfe, and Vce(sat), FET gm, etc.
Here is a shot of it:
I've also got a meter in my shop that will do a Kelvin type of resistance measurement. This is also called 4-point, or 4-wire. With this technique, there is a + and - force, and a + and - sense, making the 4-points, which enables you to measure very low resistance values.. The units here are OHMS, and you can see measuring a piece of wire results in 0.00383 OHMS, or 3.83 milliohms: